Organic light emitting display device having automatic brightness control apparatus

• US 7,639,218 B2
• Filed: 08/18/2006
• Issued: 12/29/2009
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Oh, Choon-Yul, Lee, Jae-Sung
• Primary Examiner(s): Mengistu; Amare
• Assistant Examiner(s): XAVIER, ANTONIO J
• Application Number:
  US11/506,582
• Publication Number:
  US 20070040774A1
• Time in Patent Office: 1,229 Days
• Field of Search: None
• US Class Current: 345/77
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element

Abstract

An organic light emitting display (OLED) device having an automatic brightness control apparatus that can control the luminance of the OLED device according to the brightness of ambient light. The OLED device includes a light sensor adapted to sense ambient light and produce an output voltage corresponding to the ambient light. The automatic brightness control apparatus is adapted to adjust a gamma value to the output voltage and output a gamma reference voltage. The automatic brightness control apparatus is adapted to sense a change in the ambient light by synchronizing the output voltage of the light sensor with a vertical synchronization (Vsync) signal. Accordingly, the gamma value varies with the brightness of the ambient light so that the luminance of the OLED device is controlled according to the brightness of the ambient light.

Claims

1. An organic light emitting display (OLED) device comprising:

a display panel having a plurality of pixels and adapted to display an image with luminance that varies with a brightness of ambient light;

a scan driver adapted to output a scan signal to select the pixels;

a data driver adapted to apply a data signal to the pixels selected by the scan signal;

an emission control driver adapted to apply an emission control signal to control emission of the pixels to which the data signal is applied;

a light sensor adapted to sense the ambient light and output a voltage corresponding to the sensed ambient light; and

an automatic brightness controller adapted to receive the output voltage of the light sensor, adjust a gamma value to a luminance corresponding to the output voltage, and apply a gamma reference voltage to the data driver,

wherein the automatic brightness controller is adapted to sense a change in the ambient light by synchronizing the output voltage of the light sensor with a vertical synchronization (Vsync) signal.

2. The OLED device of claim 1, wherein the automatic brightness controller comprises:

an A/D converter adapted to receive the output voltage of the light sensor, compare the output voltage of the light sensor with a reference voltage, and convert the output voltage of the light sensor to a digital signal;

a Vsync counter adapted to receive the Vsync signal, count the Vsync signal a number of times, and output the Vsync signal;

an A/D controller adapted to receive the digital signal from the A/D converter, synchronize the digital signal with the Vsync signal output from the Vsync counter, and output a control signal;

a gamma controller adapted to output one of a plurality of previously stored gamma values in response to the control signal output from the A/D controller;

a first automatic brightness controller adapted to control operations of the A/D converter, the Vsync counter, the A/D controller, and the gamma controller; and

a gamma circuit adapted to output a gamma reference voltage corresponding to one of the previously stored gamma values output from the gamma controller.

3. The OLED device of claim 2, wherein the gamma controller comprises:

a gamma register adapted to store a number of gamma values, one of which is selected when an automatic brightness control mode is turned on;

a gamma setting register adapted to store a reference gamma value that is selected when the automatic brightness control mode is turned off;

a gamma selector adapted to select a gamma value from the gamma register in response to the control signal output from the A/D controller; and

a gamma output portion adapted to output to the gamma circuit the gamma value selected by the gamma selector under the control of the first automatic brightness controller.

4. The OLED device of claim 3, wherein the gamma values comprise red, green, and blue gamma values.

5. The OLED device of claim 4, wherein the automatic brightness controller further comprises a second automatic brightness controller adapted to transmit a control signal to select the reference voltage compared with the output voltage of the light sensor to the A/D converter.

6. An automatic brightness control apparatus adapted to receive an output voltage produced by a light sensor according to ambient light and adjust a gamma value to a luminance corresponding to the output voltage of the light sensor to automatically control the luminance of an organic light emitting display device, the automatic brightness control apparatus comprising:

an A/D converter adapted to receive the output voltage of the light sensor, compare the output voltage of the light sensor with a reference voltage, and convert the output voltage of the light sensor into a digital signal;

a Vsync counter adapted to receive a vertical synchronization (Vsync) signal, count the Vsync signal a number of times, and output the Vsync signal;

an A/D controller adapted to receive the digital signal from the A/D converter, synchronize the digital signal with the Vsync signal output from the Vsync counter, and output a control signal;

a gamma controller adapted to output one of the previously stored gamma values in response to the control signal output from the A/D controller;

a first automatic brightness controller adapted to control operations of the A/D converter, the Vsync counter, the A/D controller, and the gamma controller; and

a gamma circuit adapted to output a gamma reference voltage corresponding to the gamma value output from the gamma controller,

wherein the A/D controller is adapted to sense a change in the output voltage of the light sensor by synchronizing the output voltage of the light sensor with the Vsync signal.

7. The automatic brightness control apparatus of claim 6, wherein the gamma controller comprises:

a gamma register adapted to store a number of gamma values, one of which is selected when an automatic brightness control mode is turned on;

a gamma setting register adapted to store a reference gamma value that is selected when the automatic brightness control mode is turned off;

a gamma selector adapted to select a gamma value from the gamma register in response to the control signal output from the A/D controller; and

a gamma output portion adapted to output the gamma value selected by the gamma selector under the control of the first automatic brightness controller to the gamma circuit.

8. The automatic brightness control apparatus of claim 7, wherein the gamma values comprise red, green, and blue gamma values.

9. The automatic brightness control apparatus of claim 8, further comprising a second automatic brightness controller adapted to transmit a control signal for selecting the reference voltage compared with the output voltage of the light sensor to the A/D converter.

10. An automatic brightness control apparatus adapted to control a gamma value according to an output voltage of a light sensor to automatically control the luminance of an organic light emitting display device, the automatic brightness control apparatus comprising:

an A/D converter adapted to receive the output voltage of the light sensor, compare the output voltage of the light sensor with a reference voltage, and convert the output voltage of the light sensor into a digital signal;

a Vsync counter adapted to receive a vertical synchronization (Vsync) signal, count the Vsync signal a number of times, and output the Vsync signal;

an A/D controller adapted to receive the digital signal from the A/D converter, synchronize the digital signal with the Vsync signal output from the Vsync counter, and output a control signal;

a gamma controller adapted to output one of previously stored gamma values in response to the control signal output from the A/D controller;

a first automatic brightness controller adapted to control operations of the A/D converter, the Vsync counter, the A/D controller, and the gamma controller;

wherein the A/D controller is adapted to sense a change in the output voltage of the light sensor by synchronizing the output voltage of the light sensor with the Vsync signal.

11. The automatic brightness control apparatus of claim 10, wherein the gamma controller comprises:

a gamma register adapted to store a number of gamma values, one of which is selected when an automatic brightness control mode is turned on;

a gamma setting register adapted to store a reference gamma value that is selected when the automatic brightness control mode is turned off;

a gamma selector adapted to select a gamma value from the gamma register in response to the control signal output from the A/D controller; and

a gamma output portion adapted to output the gamma value selected by the gamma selector under the control the first automatic brightness controller to the gamma circuit.

12. The automatic brightness control apparatus of claim 11, wherein the gamma controller comprises red, green, and blue gamma values.

13. The automatic brightness control apparatus of claim 12, further comprising a second automatic brightness controller adapted to transmit a control signal for selecting the reference voltage compared with the output voltage of the light sensor to the A/D converter.